Bicycle frame

ABSTRACT

The present invention is directed to a mountain bike frame ( 10 ) for use with a rear wheel ( 118 ). The frame is a “diamond-type” frame that includes seat stay tubes ( 32, 34 ). The seat stay tubes ( 32, 34 ) are spaced apart to define a gap distance (C) between the inner surface of the seat stay tubes ( 32, 34 ) at a tire intersection point that at a minimum is greater than about 2 inches. In addition, the seat stay tubes ( 32, 34 ) have a modulus of elasticity value multiplied times the moment of inertia value is between about 1.0 lb×inches 2  and about 10 lb×inches 2 . The frame is for use with only a rear disc brake mounted to one of the seat stay tubes ( 32,34 ).

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to frames for bicycles. Moreparticularly, the invention is directed to a mountain bicycle frame.

BACKGROUND OF THE INVENTION

Conventional bicycle frames use tubes joined into closed frameworks tointerconnect the components (front fork/handlebar assembly, seat,crankset, rear wheel) and transmit the loads there between. The tubesalso keep the components in spacial relation, i.e., they maintain thecomponents relative proximity.

The traditional bicycle frame includes a top tube, a relatively shorthead tube, a seat tube, a down tube, a bottom bracket, a pair of chainstays, a pair of dropouts, and a pair of seat stays. The top tubeconnects at its front end to the top of the head tube, and extendsbackward to the top of the seat tube. The down tube connects at thefront end to the bottom of the head tube and extends downwardly andrearwardly to the bottom bracket where the seat tube and the down tubeare connected. The pair of chain stays extend rearwardly from the bottomof the seat tube to the dropouts. The pair of seat stays connectdirectly or indirectly to the top of the seat tube. The seat staysextend backward from the seat tube to the dropouts. The seat staysgenerally include two seat stay tubes that converge from the dropoutstoward the seat tube. The dropouts support the rear wheel axle. Thisconventional frame design is called the “diamond” frame, because whenviewed from the side, the top tube, down tube, chain stays, and seatstays enclose a diamond-shaped space.

Such frames are used for both road bikes and mountain bikes. The terrainthat a bike is used on dictates the load requirements for the bike andthe performance characteristics of the components. For example, sincemountain bikes are used on rough terrain and often are ridden over rootsand jumps they must be more durable than road bikes, which encounterrelatively smooth surfaces.

With respect to performance characteristics, due to the ridingconditions encountered on mountain bikes, mountain bike brakes mustprovide more braking force than road bike brakes. To that end, mountainbikes are typically equipped with cantilever brakes. In order to mountcantilever brakes for use on a rear wheel, the seat stay tubes mustinclude brake bosses. The brake bosses extend generally perpendicular tothe seat stay tubes. Cantilever brakes include two separate brake armsthat are pivotally mounted on the brake bosses. A cable links the armsto a brake lever mounted on the handlebars. The other end of each armhas a pad mounted thereto. When the lever is depressed, the cable causesthe upper end of each arm lo move outward Consequently, the lower end ofeach arm and the pads connected thereto move inward and contact oppositesides of the rim of the rear wheel. Cantilever brakes apply a largebraking force to the rim.

More over, cantilever brakes exert large lateral forces on the seatstays, which has a tendency to separate the seat stays from one another.In order for the seat stays to endure these forces and to minimize thetendency for the seat stays to spread, they must meet certain stiffnessrequirements. The stiffness requirements have been met bending the seatstay tubes into various geometries, providing large diameter seat staytubes, providing tubes with increased wall thicknesses and/or usingmaterials that exhibit increased stiffness. These techniques can be usedseparately or in different combinations. However these techniques canadd weight to the frame, which is undesirable.

Some mountain bikes today are equipped for use with cantilever brakes ordisc brakes. The seat stays for such frames are robust enough to withstand use with cantilever brakes, and the seat stays have bosses forreceiving cantilever brakes. Thus, the techniques mentioned above areused to ensure that the seat stays are stiff enough for use with thecantilever brakes.

Road bikes, on the other hand, typically use caliper brakes. In order tomount caliper brakes to a frame, the seat stays generally include a seatstay bridge that extends between each of the seat stay tubes. The bridgehas a bore defined therein for pivotally mounting the caliper brakes.The caliper brakes apply less braking force than cantilever or discbrakes and require less robust seat stays. Thus, the seat stays for roadbikes are usually less stiff and lighter than mountain bikes.

The need exists for a lighter weight mountain bike frame that meets theperformance characteristics for mountain bikes.

SUMMARY OF THE INVENTION

According to the present invention a mountain bike frame for use with arear wheel is disclosed. The frame includes a head tube, a top tube, adown tube, a bottom bracket, a seat tube, a pair of dropouts, a pair ofchain stay tubes, and a pair of seat stay tubes.

The top tube extends rearwardly from the head tube. The down tubeextends substantially rearwardly and downwardly from the head tube. Theseat tube has a first portion connected to the top tube and a secondportion coupled to the down tube, such that the head tube, top tube,down tube and seat tube form a first substantially triangular firstregion. The bottom bracket is connected to the down tube and seat tube.Each chain stay tube in the pair is spaced from the other and extendsgenerally rearwardly from the bottom bracket to the associated dropout.Each seat stay tube in the pair is spaced from the other and coupled tothe top tube so that the seat stay tubes extend generally rearwardly anddownwardly from the top tube to the associated dropout. The seat staytubes define a gap distance between the inner surface of the seat staytubes at a tire intersection point that at a minimum is greater thanabout 2 inches. The seat stay tubes also have a modulus of elasticityvalue and a moment of inertia value such that the modulus of elasticityvalue multiplied times the moment of inertia value is between about 1.0lb×inches² and about 10 lb×inches².

In one embodiment, the frame is for use with a rear disc brake coupledto one of the seat stays.

In yet another embodiment, the present invention is directed to abicycle including the above frame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear, perspective view of a bicycle frame in accordance withthis invention;

FIG. 2 is a rear view of the frame of FIG. 1;

FIG. 3 is a side view of the frame of FIG. 1;

FIG. 4 is a side view of a bicycle incorporating the frame of FIG. 1;

FIG. 5 is a partial, rear view of the bicycle of FIG. 4;

FIG. 6 is a rear, perspective view of another embodiment a bicycle framein accordance with this invention; and

FIG. 7 is a rear view of the frame of FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 and 2 illustrate bicycle frame 10 in accordance with the presentinvention. The bicycle frame 10 is a “diamond” type frame and includes ahead tube 12, a top tube 14, a down tube 16, a seat tube 18, and a reartriangle assembly 20. The head tube 12 is generally vertical. The toptube 14 extends rearwardly from the top of the head tube 12 and ends ata first portion on the seat tube 18. In this embodiment, the firstposition is near the upper end of the tube however the first portion canbe elsewhere such as centrally disposed on the seat tube.

The down tube 16 extends rearwardly from the bottom of the head tube 12.The seat tube 18 is generally vertical and has a bottom bracket 22connected to the lower end. The down tube 16 is joined to the bottombracket 22 and the bottom of the head tube 12. As shown in FIG. 3, thehead tube 12, top tube 14, down tube 16 and seat tube 18 form a firstsubstantially triangular region T1.

As shown in FIGS. 1 and 2, the rear triangle assembly 20 generallyincludes a seat stay assembly 24, a chain stay assembly 26, and a pairof rear dropouts or brackets 28 and 30. The seat stay assembly 24includes a pair of seat stay tubes 32 and 34 that are coupled to the toptube 14 through the seat tube 18. The seat stay tubes 32 and 34 extendfrom opposite sides of the top of the seat tube 18 and end at thedropouts 28 and 30, respectively. In another embodiment, the seat staytubes can be connected directly to the top tube, and the top tubeconnected to the seat tube. Disc brake bosses 33 are coupled tot theseat stay tube 34. In this embodiment, the bosses are formed integrallywith the dropout 30. In another embodiment the bosses can be near thedropout. The disc brake bosses 33 define bores 33 a in the dropout. Inanother embodiment, various numbers of bosses, such as one.

As best seen in FIG. 2, the seat stay tubes 32 and 34 converge towardone another from the dropouts 28 and 30 to the seat tube 18. Each seatstay tube 32 or 34 is formed of two sections 32 a-b or 34 a-b,respectively. The first section 32 a or 34 a is closest to the seat tube18 and the second section 32 b or 34 b is closest to the dropouts 28 and30. The first and second sections 32 a and 32 b are disposed at an angleto one another. The first and second sections 34 a and 34 b are alsodisposed at an angle to one another. The second sections 32 b and 34 bare curved.

Referring to FIGS. 1 and 2, the seat stay assembly 24 further includes aseat stay bridge member 36. The seat stay tubes 32 and 34 are joinedtogether by the laterally extending seat stay bridge member 36. The seatstay bridge member 36 extends between the first sections 32 a and 34 aof the tubes 32 and 34. The bridge member 36 is disposed at a locationspaced upwardly from a tire intersect point P.

The chain stay assembly 26 includes a pair of chain stay tubes 38 and40. and a chain stay bridge member 42. The chain stay tubes 38 and 40extend from opposite sides of the bottom bracket 22 and end at thedropouts 28 and 30, respectively. Each chain stay tube 38 and 40 has twosections that are at an angle to one another. The chain stay tubes 38and 40 are joined together by the laterally extending chain stay bridgemember 42 that extends between the first section 38 a and 40 a of thetubes 38 and 40. As shown in FIG. 3, the seat tube 18, seat stay tubes34, chain stay tubes form a second substantially triangular region T2.

Referring to FIG. 1, the seat stay tube 34 is shorter than the seat staytube 32 by at least 5% to accommodate the dropout 30 instead of thedropout 28. The chain stay tube 40 is shorter than the chain stay tube38 by at least 5% to accommodate the dropout 30 instead of the dropout28.

Referring to FIGS. 2 and 3. each annular seat stay tube 32 and 34 has adiameter represented by the arrows labeled d_(S). Each oval chain staytube 38 and 40 has diameters represented by the arrows labeled d_(C1)and d_(C2) (as shown in FIGS. 3 and 3B).

Referring to FIGS. 3 and 3A, each seat stay tube 32 and 34 is a hollowtube having a center C_(S). An outer radius of each seat stay tube isdefined by the arrows R_(OS) An inner radius of each seat stay tube isdefined by the arrows R_(IS). A wall thickness is equal to the outerradius R_(OS) minus the inner radius R_(IS) and defined by the arrowsT_(S) ^(R).

Referring to FIGS. 2, 3 and 3B, each chain stay tube 38 and 40 is ahollow tube having a center C_(C). The chain stay tube is oval andreferences two axii A1 and A2 that are perpendicular to one another andthe longitudinal axis L of the frame. The first axis A1 extendsvertically and the second axis A2 extends laterally. The chain stay tubediameter d_(C1) is defined parallel to the axis Al. The chain stay tubediameter d_(C2) is defined parallel to the axis A2.

A first outer radius of each chain stay tube is defined by the arrowsR_(OC1) and is parallel to the axis A1. A first inner radius of eachchain stay tube is defined by the arrows R_(IC1) and is parallel to theaxis A1. A first wall thickness is equal to the first outer radius minusthe first inner radius and defined by the arrows T_(C1).

A second outer radius of each chain stay tube is defined by the arrowsRock and is parallel to the axis A2. A second inner radius of each chainstay tube is defined by the arrows R_(IC2) and is parallel to the axisA2. A second wall thickness is equal to the second outer radius minusthe second inner radius and defined by the arrows T_(C2). The first wallthickness T_(C1) is equal to the second wall thickness T_(C2).

The components of the frame are formed of aluminum and joined togetherby conventional techniques such as welding, soldering, brazing fusing,and the like, as known by those of ordinary skill in the art. Therecommended material is aluminum 6061-T6, which is commerciallyavailable from various manufacturers. However, other aluminum materialscan also be used.

Using the recommended aluminum and frame configuration, the diameter ofthe seat stay tubes ds is less than both of the diameters of the chainstay tubes d_(C1) and d_(C2). Most preferably, the diameter of the seatstay tubes d_(S) is 0.625 inches. If another material is used, thediameters of the tubes may be modified. For example, titanium, steel,metal alloys, composite materials, such as carbon, or the like can beused.

The bending stiffness or moment of Inertia (1) in inches₄ for the seatstay tubes which have an annular cross-section is calculated using theequation:$I = {\frac{\pi}{4}\left\lbrack {d_{SO}^{4} - d_{St}^{4}} \right\rbrack}$

where,

d_(SO)=outer diameter of seat stay; and

d_(SI)=inner diameter of seat stay.

The modulus of elasticity value (E) for the recommended aluminum is 10.1E⁶ psi that forms the inventive frame. Other materials have differentmodulii of elasticity values.

Referring to Table 1, the moment of inertia value of the seat stay tubesis compared for various frames. The frame of Example 1 is a conventionalmountain bike frame with seat stay tubes having a diameter of 0.875inches and a wall thickness of 0.049 inches. The frame of Example 2 isthe inventive mountain bike frame with seat stay tubes having a diameterof 0.625 inches and a wall thickness of 0.028 inches.

TABLE I Seat Stay Tube Characteristics For Aluminum Frames MeasurementExample 1 Example 2 Seat Stay Tube Diameter (inches) 0.875 0.625 SeatStay Tube Wall Thickness (inches) 0.049 0.028 Seat Stay Tube OuterRadius (inches) 0.4375 0.3125 Seat Stay Tube Inner Radius (inches)0.3885 0.2845 Seat Stay Tube Moment of Inertia (inches⁴) 0.011 0.002 EI(lb × inches²) 12.18 2.22

The conventional frame of Example 1 in comparison to the inventive frameof Example 2 having the seat stays as discussed above has an EI valuesubstantially greater than the EI value of the inventive frame. Thus, EIvalue accounts for the diameter of the seat stay tubes and the materialof which it is formed. For the inventive frame, the recommended EI valueis between about 1 lb×inches² and about 10 lb×inches². More preferably,the EI value is between about 1 lb×inches₂ and about 5 lb×inches₂. Stillmore preferably, the EI value is about 2 lb×inches² and most preferablythe EI value is about 2.2 lb×inches². Other materials and diameters canbe combined so that the frame exhibits the EI value that falls withinthe above range is used in the inventive frame. It is preferred that theinventive frame has a moment of inertia value determined using thediameters in Table I.

The inventive frame weighs substantially less than the conventionalframe. A significant weight savings of about 120 grams for a frameweighing about 1600 grams is achieved.

As shown in FIG. 4, a bicycle 100 includes the inventive frame 10. Thebicycle includes components that are available in the industry, but thecomponents do not constitute part of the invention. For example, thehead tube 12 has a suspension system 102 mounted therein. One end of thesuspension system 102 has the handlebars 104 connected thereto, and theother end has front fork 106 extending outwardly and downwardlytherefrom. The front fork 106 has the front wheel axle 108 securedthereto for rotatably supporting a front wheel 110. The seat tube 18accepts seat 112 mounted on a standard seat post 114, and the bottombracket 22 accepts a pedal assembly 115 that includes a crankset. Afront brake assembly (not shown), gears and shifters 116 a and b, andchain 117 are also used with the bicycle. These components are known inthe art.

The bicycle 100 further includes a rear wheel 118 whose axle 120 issupported by the dropouts 30 and 28 (shown in FIG. 3). The bicycle 100also includes a disc brake assembly 122. The disc brake assembly 122includes a disc rotor 124, a brake lever 125, a caliper 126, and a fluidline 128. The disc rotor 124 is fixedly secured to the rear axle 120 sothat when the rear wheel 118 and the rotor rotate 124 together. Thebrake lever 125 is mounted on the handle bars 104. The caliper 126 ismounted on the dropout 30 using the bosses 33 and bores 33 a (as shownin FIG. 1).

The caliper 126 further includes two opposing, movable pistons (notshown) that when mounted are on opposite sides of the rotor 124. Thefluid line 128 connects the lever 125 to one end of the pistons in thecaliper 126. The fluid line contains a flowable hydraulic fluid. Theother end of the pistons has pads (not shown) mounted thereon.

When the lever 125 is actuated, the fluid within the line 128 moves andcauses the caliper 126 pistons to move the pads against the rotor 124 inpincer-like fashion to apply a braking force to the rotor 124. When thelever 125 is released, the fluid within the line 128 moves and causesthe piston to fully retract the pads to end the braking force on therotor.

One recommended disc brake assembly that is commercially available ismanufactured by CODA under the name Compact Disc Brake. However, otherbicycle disc brakes can be used with the frame of the present invention,such as those with cables.

Referring to FIG. 5, the rear wheel 118 will be discussed in moredetail. However, the disc brake assembly 122 (as shown in FIG. 4) hasbeen removed for clarity. The rear wheel 118 includes a hub 130, a rim132, a plurality of spokes 133. a tire 134 and an inner tube 136.

The hub 130 includes a tubular axle portion 138 and axle ends 140extending perpendicular to the axle portion 138 at both ends thereof.The hub 130 also includes bearings (not shown) and the rear axle 120extends through the axle portion 138 of the hub.

The rim 132 is an annular structure having a bottom wall 142 andsidewalls 144 extending from both sides perpendicular to the bottom wall142. The spokes 133 are connected at one end to the inner surface of therim 132 and at the other end to the axle ends 140 at spacedcircumferential locations.

The tire 134 is also annular and has free ends which are locatedadjacent the sidewalls 144 of the rim 132 so that a chamber is definedtherein for receiving the inner tube 136. When the inner tube 136 isinflated the tire 134 also inflates and is forced against the rimsidewalls 144.

The width of the tire, once inflated, is designated by the arrows W_(T).The narrowest distance between the seat stay tubes 32 a-b and 34 a-b islocated at a point P. Each space between the inflated tire and the seatstay tubes at the tire intersect point P has a distance C, referred toas the tire clearance. The total tire clearance is the sum of the twotire clearance measurements.

For mountain bike tires, the tire width W_(T) is between about 1.8inches and about 2.3 inches. The clearance C is typically about 0.25inches. Referring to FIG. 4, the radius of the wheel 118 is designatedby the arrow R_(T). The radius R_(T) is typically between about 12.9inches and about 13.1 inches. Referring to FIG. 5, a distance D betweenthe dropout 30 and the tire intersect point is less than about 13.2inches and more preferably between about 12.9 inches and about 13.1inches.

For comparison, road bike tires typically have a tire width less thanthat of mountain bikes and a radius greater than that of mountain biketires. For example, the tire width for a road bike tire is between about0.75 inches and about 1.1 inches. The clearance C is typically about0.25 inches. The radius of a road bike tire is typically between about13.25 inches and about 13.5 inches.

The seat stays 32 a-b and 34 a-b have a gap distance G between the seatstays, which is the sum of the tire width and total clearance. The gapdistance is also the width between the inner surfaces of the seat staysat the point P. For mountain bikes, the gap distance is greater thanabout 2.0 inches, more preferably the gap distance is between about 2inches and about 3.5 inches, and most preferably the gap distance isbetween about 2.3 inches and about 2.8 inches. The gap distance for roadbikes is between about 0.8 inches and 1.6 inches.

Referring to FIGS. 6 and 7, another embodiment of a bike frame 10′ isshown. The bike frame 10′ has elements similar to the frame 10 (as shownin FIG. 1). Similar elements have the same reference number followed bya prime symbol. The seat stay assembly 24′ has been modified so that theseat stay tubes 32′ and 34′ are joined by a curved section. At thecurved section the seat stay assembly has a strut tube 36″ that connectsthe seat tubes 32′ and 34′ to the seat post 18′. The seat tubesotherwise have the same configuration as that discussed above. Thisconfiguration allows stiffness to be achieved in a different way than inthe first embodiment.

While it is apparent that the illustrative embodiments of the inventionherein disclosed fulfill the objectives stated above, it will beappreciated that numerous modifications and other embodiments may bedevised by those skilled in the art. For example, although the firstembodiment is shown with a constant diameter and wall thickness, inanother embodiment the diameter and wall thickness can be varied alongthe length of the seat stay tubes so long as the average of the modulusof elasticity and moment of inertia along the length is within theabove-identified range. Another modification includes using the frameand seat stay configuration of the first embodiment without the seatstay bridge member. Various other features of the embodiments can becombined. Furthermore, the frame can be modified so that the tubes arecoupled in different ways than shown while providing the first andsecond triangular regions. Therefore, it will be understood that theappended claims are intended to cover all such modifications andembodiments which come within the spirit and scope of the presentinvention.

What is claimed:
 1. A bicycle frame for use with a rear wheelcomprising: a head tube; a top tube extending rearwardly from the headtube; a down tube extending substantially rearwardly and downwardly fromthe head tube; a seat tube having a first portion connected to the toptube and a second portion coupled to the down tube, such that the headtube, top tube, down tube and seat tube form a first substantiallytriangular region; a bottom bracket connected to the down tube and seattube; a pair of dropouts; a pair of chain stay tubes spaced from oneanother and extending generally rearwardly from the bottom bracket tothe associated dropout; and a pair of seat stay tubes coupled to the toptube and extending generally rearwardly and downwardly from the top tubeto the associated dropout, such that the seat tube, pair of chain staytubes, and pair of seat stay tubes form a second substantiallytriangular region, and the pair of seat stay tubes further being spacedfrom one another and defining a gap distance between the inner surfaceof the seat stay tubes at a tire intersect point that is greater thanabout 2 inches, and the seat stay tubes having a modulus of elasticityvalue multiplied by a moment of inertia value being between about 1.0lb×inches² and about 10 lb×inches².
 2. The frame of claim 1, furtherincluding a seat stay bridge member extending between the seat staytubes at a location spaced upwardly from the tire intersect point. 3.The frame of claim 1, wherein the seat stay tubes are connected to theseat tube.
 4. The frame of claim 1, wherein the first portion of theseat tube is adjacent the upper end of the seat tube.
 5. The frame ofclaim 1, wherein the first portion of the seat tube is centrallydisposed on the seat tube.
 6. The frame of claim 1, further including aseat stay strut, the seat stay tubes being joined by a curved section,and the seat stay strut extending between the seat tube and the curvedsection.
 7. The frame of claim 1, wherein the frame includes a discbrake boss coupled to one of the seat stay tubes near the associateddropout.
 8. The frame of claim 1, wherein the seat stay tubes having anannular cross-section with a wall thickness being less than about 0.03inches and an outer diameter being less than about 0.800 inches.
 9. Theframe of claim 1, wherein a distance between the dropout and the tireintersect point is less than about 13.2 inches.
 10. The frame of claim1, a distance between the dropout and the tire intersect point isbetween about 12.9 inches and about 13.1 inches.
 11. The frame of claim1, further including the moment of inertia value being less than 0.05inches⁴.
 12. The frame of claim 8, wherein the frame is formed ofaluminum.
 13. The frame of claim 1, further including the moment ofinertia being about 0.002 inches⁴.
 14. The frame of claim 10, furtherincluding the modulus of elasticity value being about 10.1E⁶.
 15. Theframe of claim 1, further including the modulus of elasticity valuemultiplied times the moment of inertia value being between about 1lb×inches² to about 5 lb×inches².
 16. The frame of claim 1, furtherincluding the modulus of elasticity value multiplied times the moment ofinertia value being about 2.2 lb×inches².
 17. The frame of claim 1,wherein the frame is formed of titanium.
 18. The frame of claim 1,wherein the frame is formed of steel.
 19. The frame of claim 1, whereinthe frame is formed of a composite material.
 20. The frame of claim 1,wherein the gap distance is between about 2 inches and about 3.5 inches.21. The frame of claim 1, wherein the gap distance is between about 2.3inches and about 2.8 inches.
 22. A bicycle comprising: a frame includinga head tube, a top tube extending rearwardly from the head tube, a downtube extending substantially rearwardly and downwardly from the headtube, a seat tube having a first portion connected to the top tube and asecond portion coupled to the down tube, such that the head tube, toptube, down tube and seat tube form a first substantially triangularregion, a bottom bracket connected to the down tube and seat tube, apair of dropouts, a pair of chain stay tubes spaced from one another andextending generally rearwardly from the bottom bracket to the associateddropout, and a pair of seat stay tubes coupled to the top tube andextending generally rearwardly and downwardly from the upper end of theseat tube to the associated dropout, such that the seat tube, pair ofchain stay tubes, and pair of seat stay tubes form a secondsubstantially triangular region, and the pair of seat stay tubes furtherbeing spaced from one another and defining a gap distance between theinner surface of the seat stay tubes at a tire intersect point that isgreater than about 2 inches, and the seat stay tubes having a modulus ofelasticity value multiplied by a moment of inertia value being betweenabout 1.0 lb×inches² and about 10 lb×inches², a front wheel assemblyincluding a front wheel rotatably connected to one end and handlebarsconnected to the other end, and the front wheel assembly being connectedto the head tube of the frame; a rear wheel rotatably connected to thedropouts of the frame; a seat is mounted on a seat post, and the seatpost is disposed within the seat tube; a pedal assembly is operativelyconnected to the bottom bracket and the rear wheel; and a disc brakeassembly is mounted on the frame.
 23. The bicycle of claim 22 whereinthe frame includes a disc brake boss coupled to one of the seat staytubes near the associated dropout for mounting the disc brake assemblyone of the seat stay tubes.
 24. The bicycle of claim 23, furtherincluding a rear axle for supporting the rear wheel, and wherein thedisc brake assembly further including a disc rotor fixedly secured tothe rear axle; a brake lever mounted on the handlebars; a calipermounted on the disc brake boss, the caliper having an engaged and adisengaged position, such that in the engaged position the caliperclamps the rotor and in the disengaged position the caliper is spacedfrom the rotor; and a fluid line containing a fluid operativelyconnecting the lever to the caliper.
 25. The bicycle of claim 23,further including a seat stay bridge member extending between the seatstay tubes at a location spaced upwardly from the tire intersect point.26. The bicycle of claim 23, wherein a distance between the dropout andthe tire intersect point is less than about 13.2 inches.
 27. The bicycleof claim 23, wherein the modulus of elasticity value multiplied timesthe moment of inertia value is about 2 lb×inches².